Carbon-pile support



Dec. 8 1925.

P. 11. CHANDEYSSON CARBON FILE SUPPOR T Filed Oct. 13, 1922 2sheets-shew 1 Dec- 8, 1925- v P. I. CHANDEYSSON 4 CARBON FILE SUPPORTFiled Oct. 13. 1922 2 Sheets-Shunt 2 Patented Dec. 8, 1925.

UNITED PIERRE I. CHANDEYSSON, 015 ST. LOUIS, MISSOURI, ASSIGNOR T MARSLLELEC- TRIO COMPANY OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINQIS-BARRON-FILE SUPPORT.

. Application filed October 13, 1922. Serial No. 594,387.

To all whom it may concern:

Be it known that I, PIERRE l. GHANDEYS- soN, citizen .of the UnitedStates, residing at St. Louis, in the county of St. Louis and State ofMissouri, have invented certain new and useful Improvements in aCarbon-Pile Support; and I do hereby declare the following to be a'full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

My invention relates 'to the'class of rheostats in which the resistanceis varied by chan ing the compression of a resistance materia such as apile of carbon disks. Viewed in some of its general aspects, myinvention aims to provide means for eliminating the interference offriction with the sensitiveness and uniformity of response of theresistance material to changes in compression, for preventing a tiltingor canting of portions of the resistance such as would interfere withthe proper response in resistance to variations in pressure, and foraffording an arrangement of parts in which the variations in resistancewill be closely roportioned to the variations in pressure. urthermore,my invention aims to provide a rheostat of this general class which willbe simple and inexpensive in construction, which can readily be adjustedas to the range of resistance afforded by the same. which will permit awide range of resistance to be secured in response to a small amount ofchange-actuating energy, and which will lend itself equally well toembodiments in which the actuating-energy is to effect either anincrease or a decrease of'the resistance.

Whilecompressible resistances of the gensure has commonly been exertedin such a way as to tend torot-ate, tilt or otherwise shift the relativeposition of the carbon disks comprising the pile, thereby introducingboth a waste of energy in the mechanism eral type of carbon pileshavelong been em-.

on a rigid support and the variation in presi employed for varying thecompremion and an uncertainty as to the effective resistance securedwith any particular position of this mechanism. Both this waste ofenergy and the uncertainty as to the resulting resistance have beenfurther increased by the friction of the disks against the tubeinclosing the same and by the friction in the mechanism employed forvarying the compression. Consequently, rheostats of this class havebeenlimited as to the purposes for which they could be commerciallyemployed and have been barred from many fields for which a carbon pileshould form an ideal resistance.

Moreover, the mechanisms commonly employed for varying the compressionof a compressible resistance have disregarded the fact that the changein resistance does not vary uniformly with pressure but varies accordingto a hyperbolic function of the pressure. Consequently, where themovement of the actuating member is substantially in proportion to theactuating effort, as in the case of a solenoid core moved by the flow ofcurrent through the solenoid, the resulting change in pressure did notre-v spond with any uniformit to the changes in the. actuating effort,an mechanism employing cams or the like for correcting this discrepancyhas introduced such complications and such friction as to becommercially prohibitive for many purposes.

My present invention aims to overcome all of the above named objectionsto rheostats of the compressible resistance type and aims to do so byemploying anexceedingly simple and durable arrangement of parts. Forthis purpose, my invention aims to provide a construction in which thecarbon pile is movable as a unit and is not su ported by the tube orother'guide which malntains the carbon disks in alinement, and one inwhich the pressure is applied to the carbon pile axially of the latterso as to revent any relative movement of the constituent disks, therebyeliminating the heretofore objectionable friction and uncertainty ofthe-resulting resistance. It also aims to? provide an arrangement inwhich the pressure ap plied to the carbon pile will be a hyperbolic 1function of the movement of the actuating member, so that by suitablypro rtioning the various parts I can make this yperbolic relationcorrespond to the above mentioned relation between the variations ofpressure 11 and resistance in a carbon pile and hence can make theresulting resistance uniformly responsive to the movement of theactuating member. Furthermore, myinvention aims to accomplish this lastnamed purpose by provldlng an exceedingly simple construcflow of currentthrough an electromagnet.

. and

Still further and also more detailed ob ects will a pear from thefollowing specification om the accompanying drawings, in which Fi 1 is asomewhat diagrammatic view of an e ectrically controlled rheostat embodyingmy invention and arranged for having the resistance decreased 1nresponse to an increase of current through an electro- 7 system employedin Fig.

ma et. a

ig. 2 is a similar view showing an embodiment in which the pressure isincreased in response to the flow of current through an electro-magnet.

Fig. 3 is a similar view showing an embodiment arranged after thegeneral principle of Fig. 1 and including adjustable means for varyingthe range of compression of the resistance.

Fig. 4 is'a somewhat diagrammatic view of another embodiment in whichthe resistance is, decreased in response to an increase ofcurrent'flowing throughan electro-magnet, namely one in which the longermember of the triangular system is stationary and in which the actuatingeffort is imparted to one of the shorter sides of the triangle.

Fig. 5 is a diagrammatic view of the triangular system forming the basisof operation of Fig. 1.

Fig. 6 is a similar diagram showing the Fig. 7 is a pers ectlve view ofan electrically controlled r eostat embodying my invention and employingthe underlying princi 10 of Figs. 1 and 5.

ig. 8 is a central and longitudinal section through the resistancemember of Fig 7. 4

ig. 9 is a front elevation of the electrically controlled rheostat ofFig. 7 with some of the parts in section, showing the movable portionsshown in full lines in the maximum compressing position and with dottedlines showing a position in which the electromagnet has eflected aconsiderable releasing of the compression.

Referring first to the more diagrammatic views, Fig. 1 shows a supportinmember 1 equipped with a conical or knif e-edge projection 2 which issocketed in a corresponding recess formation in one of the end plates 3of a compressible resistance comprising a pile of carbon disks' islidably inserted in an insulating tube 5, the carbon disks beinginsulated from the pressure applying heads 3- by insulating disks 6. Theend piece, or pressure-transmitting head 3 at the other end of thisresistance member also has a corresponding recess formation entered by asuitably pointed pro'ection 7 on a swinging arm 8 which forms t eactuating member of the appliance. This member .8 carries anotherprojection 9 entering a recess formation in the support 1 out ofalinement with the axis of the resistance member. Thus ar ranged, therigid portion of the support disposed between the and 9 corresponds tothe thrust arm T of the diagram of Fig. 5, while the compressibleresistance corresponds to the arm R of that figure and the actuatingmember corresponds to the arm 8 of the latter figure.

This actuating arm is longer than either of the two other arms and thearms T and R form an oblique angle with each other. By making this anglea'fairapproach to 180 and assuming the thrust member T' to bestationary, it will be evident that a pivotal movement of the arm 8about the apex 9 tips of the projections 2 I of the triangulatedmechanism will com- 7 press the resistance member R.

Consequently, in the embodiment of Fig. 1, gravity will have thiscompressing effect, while the lifting action of an electromagnetic coil10 on an arm core 11 carried by the actuating arm 8 willswing the arm 8in the direction of the arrow 12 of Fig. 5, thereby releasing thecompression and correspondingly changing the resistance. F urthermore,since the variation in compression of the member R in a system of threepivotally interconnected members arranged after the manner of Fig. 5 isa hyperbolic function of the extent of pivotal movement of the arm 8about the pivot apex 9, I secure a change in compression correspondingin general relationship to that which exists between the amount ofcompression in a carbon pile and the resulting resistance. B suitablyproportioning the various parts of the system of Fig. 5 I can thereforecause the change in resistance to be approximately uniformlyproportioned to the extent of movement of the actuating member, which ishighly desirable.

However, the mechanism of Fig. 1 can readily be inverted effectivelyafter the manner of Fig. 2, so as to have the compression relaxed by theeffect of gravity on the actnating arm, while the lifting efi'ect of theelectro-magnet swings the actuating arm so as to increase thecompression, the principle employed then by an inversion of that of Fi5.

In practice, I desirably also provide means for initially adjusting thecompression of the resistance member, thereby predetermining the generalrange of resistance aftorded by my mechanism. Thus. Fig. 3 shows asomewhat diagrammatic view corresponding in operating principle to thatof hi 1 but having the thrust tip 7 on one on of the actuatin arm formedupon a screw 13 which is ad ustable with respect to the arm 8.Furthermore, while I have heretofore pictured and described embodimentsof my invention in which the relatively short thrust arm T of the systemis stationary and in which the actuating eflort is applied to the longerarm 8, I do not Wish to be limited as to any such features ofconstruction or arrangement. For example, Fig. 4 shows an embodiment inwhich the long arm 14 is stationary and forms the support for the otherarms, and in which the magnet coil 10 is arranged for moving a core 11mounted on a movable thrust member 15, the resistance member in thiscase being disposed between.

this movable thrust member and an adjusting screw 13 threaded upon thelonger stationary member 14. In this case, the system of forces is moreafter the manner of Fig. 6, it being obvious that the general principleof my invention can be employed in any arrangement which tends to bringthe members T and R of the system more nearly into alinement with thelonger arm, or which varies the distance between the longer arm and thepivotal juncture of the arms R and T.

As a practical exemplification of my invention, Figs. 7 and 9 show anelectrically controlled rheostat in which a backplate 15 serves as thesupport for the appliance as a whole. This plate has a pair of webs 16between which a magnet coil or spool 17 is secured by screws 18, thelower web 16 being perforated to clear an iron core 19 which extendspart way up into the coil and which is carried by one end of theactuating arms 20 of the rheostat. The other end of the arm 20 has arecess facing the magnet coil and affording a pivotal bearing for theouter end of a thrust member 21, this thrust member being a pin whichextends through a lug 22 on the back plate and which is securedto thislug by a screw 23. Adjacent to the magnet coil the actuating arm 20carries a rigid riser 25 through which an adjusting screw 13 isthreaded. This screw is normally locked against movement by locknuts 26and has a pointed tip extending toward the pointed tip 24 ofthe thrustmember 21.

Interposed between the said two pointed tips is the resistance memberottheappliance, consisting of a pile of carbon disks fl operativelyinterposed between two end disks or pressure applying members 3, each ofthe latter having an outwardly directed recess formation disposed axialof the pile of disks and entered by one of the said pointed tips. Thecarbon disks are insulated from the end disks 3 by interposed insulaoing disks 6, all of the said elements 4, 6 and 3 being retained inoperative alinement by suitable guide means such as an insulating tube 5slidably housing the same.

With the parts thus arranged, it will be obvious that gravity tends toswing the right hand or free end of the actuating arm downwards, therebytending to brings-the axis of the resistance more nearly into alinem'entwith the effective axis of the thrust member,

the latter axis being that shownin dotted lines in Fig. 9. With theactuating arm constructed as a rigid member, any such downward movementof the actuating arm willdeerease the effective length of the resistancemember, thereby compressing the carbon pile. However, any raising of theactuating arm against the action of gravity by the attraction of themagnetic coil 17 on the core 19 will tend to increase the distancebetween the said pointed tips and hence will relax the compression. Byadjusting. the

osition of the screw 13 with respect to the ug 25 I can readily adjustthe initial compression of the resistance, while by varying the diameterand quality of the carbon disks I can readily vary the carrying capacityand can secure further changes in the general range of the obtainableresistance. So also,

by substituting magnet spools of different windings I can readily changethe respon- 'siveness of the rheostat to various electrical llObodiments of my invention, it being obvious extending at acute angles toboth of the other arms; and means for relatively moving the said armswhile maintaining their said pivotally connected disposition so as tovary thev size of the said acute angles and the effective length of thecompressible re sistance arm.

2. A rheostat comprising in substantially triangular formationastationary thrust arm. a resistance arm pivoted at one end to one endofthe thrust arm and extending in 'oblique continuation of the thrust arm,and

a third arm longer than the resistance arm,

the third arm being rigid and directly pivoted-at its ends respectivelyto the other ends of the .thrust arm and of the resistance arm, theresistance arm having as a part thereof a resistance adapted to becompressed when the third arm is moved about its pivotal connection tothe thrust arm toing the longer arm in the opposite direction withrespect to the thrust arm.

5. -A rheostat comprising a pair of rigidlv spaced pivots, incombination with a rigid arm and a compressible resistance pivotallyconnected to each other and respectively fulcrumed u on the said pivots,the resistance being entirely supported through its pivotal connectionsto the said arm andto the pivot upon which the resistance is fulcrumed.

6. The combination with a compressible resistance medium whose rate ofresistance variation is substantially a hyperbolic function of thecompressing pressure applied to the resistance medium, of thrust meansen-- gaging one end .of the resistance medium to resist a bodilymovement of the said medium, a compressing member movably mounted withrespect to the'thrust means, and actuating means-operatively connectedto the compressing member for moving the latter at a rate which is alsoa hyperbolic function of the compressing pressure applied to theresistance through the compressing member by the movement of the latter.

7. In combination, a compressible resistance, thrust means pivotallyconnected to theresistance at one end, and a lever pivotally connectedto the other end of the resistance and cooperating with the thrust meansin afiording the entire support for the resistance.

8. The combination with guide means of an assemblage of disks freelyslidable with respect thereto, the said assemblage including metal enddisks, compressible reslstance disks disposed between the end disks, andm sulating elements respectively insulating the end disks from theresistance disks; and compressing means engaging the endward faces ofthe end disks to clamp the 'said assemblage of disks, the saidcompressing means forming the sole support for the assemblage of disksand the guide means.

9. A resistance member including a' car'- bon pile. a thrust memberhaving one end thereof in pivotal engagement with one end of theresistance member, a relatively longer member having two portionsthereof respectively in engagement with the other ends of the thrustmember and the resistance member, the last named two members extendingin continuation of each other and at a rela tively large angle to eachother, the resistance member being supported solely by the said othertwo members.

10." A rheostat comprising a pair of ri idly spaced pivots, and a pairof pivota y joined arms fulcrumed at their free ends respectively uponthe said pivots, the said arms extending at an acute angle to eachother, one of the said arms having a compressible resistanceconstituting the main portion thereof, a solenoid core fastupon one ofthe said arms, and a magnetizing coil associated with the core to movethe latter so as to vary the said angle.

' 11. In combination with a compressibleresistance, means having a partpivotally engaging an end of the resistance, and rigid means having apart movably engaging the opposite end of the resistance and having asecond part movably engaging the first named means at a point to oneside of the axis of the resistance whereby upon relative movementbetween the resistance and rigid means in one direction the resistancewill be compressed and upon movement in a second direction thecompression will be relaxed, the resistance being entirely supported byits engagement with the said parts.

12. A rheostat comprising a pair of rigidly spaced pivots, incombination with a rigid arm and a compressible resistance pivotallyconnected to each other and respectively fulcrumed upon' the saidpivots, the resistance being entirely supported thgough its pivotalconnections to the said arms and to the pivot upon which the resistanceis fulcrumed, and means associated with the resistance for varying theefl'ective length thereof so as to adjust the initial compression of theresistance.

13. The combination with a carbon pile, of a pair of heads between whichthe pile is interposed, and two rigid thrust members respectivelyengaging the said heads, each thrust member having substantially a pointengagement with the adjacent heads, one of the thrust members extendingin oblique extension of the axis of the carbon pile, the other thrustmember extending at an acute angle to the said axis past both the carbonpile and the aforesaid thrust member and being pivoted to the outer endof the latter, the carbon pile being supported solely by the saidengagement thereof with the thrust 10 members.

14. The combination of a resistor 'whose conductivity is Variable bycompression of compression-varying means engaging the same and formingthe sole support for the resistor, the supporting and compressingengagement between the said means and the resistor being confined to apoint brknifeedge bearing at each end of the resistor.

Signed at St. Louis, Missouri, October 10th, 1922.

PIERRE I. GHANDEYSSON.

